var arreglo

function MakeArray(n) {
   this.length = n;
   for (var i = 1; i <= n; i++) { 
     this[i] = 0 }
   return this
}

function deleteAllOptions (select) {
  select.options.length = 1;
}

function modelos(marca, modelo) {
   this.marca = marca;
   this.modelo = modelo;
}